1. Field of the Invention
This invention relates generally to plug-in type electrical apparatus having stab connectors and more particularly electrical apparatus having stab connectors and utilizing electromagnetic repulsion forces for generating contact pressure.
2. Description of the Prior Art
In plug-in type electrical apparatus, a terminating system is utilized that is generally comprised of a main bus arrangement disposed to receive a plurality of parallel contact fingers which make contact at each side of the bus having some biasing means to maintain pressure between the contact fingers to form a desirable electrical connection with the bus means therebetween. Sufficient pressure must be maintained on the contact fingers because if they should part arcing and overheating may result and serious damage to the bus means and electrical connectors may also result. When a large current flows, these fingers are pulled together by electromagnetic attractive forces. For smaller currents, springs or other biasing means are provided to maintain contact force. One example of such a system is disclosed in U.S. Pat. No. 3,869,192 issued to Alfred E. Maier, et al. on Mar. 4, 1975 and assigned to the assignee of the present application. The number of contact fingers utilized and the contact force applied is chosen to meet both the thermal and current-carrying capabilities of the apparatus. However, in designing plug-in type electrical apparatus to maintain a predetermined contact pressure, it has been found that for higher contact pressure requirements, it is increasably difficult to plug in the electrical apparatus. Forcing the electrical apparatus in place can result in damage to the bus means and also cause damage to the biasing means utilized for maintaining the electrical contact pressure.